Conformal expansion of prosthetic devices to anatomical shapes

ABSTRACT

A system for expanding a device in a conduit or orifice of a human body includes an expansion device that is movable from a first configuration to a second configuration. External surfaces of the expansion device can collectively have a non-cylindrical cross-section relative to a main axis of the expansion device, such that the external surfaces of the expansion device generally conform to the anatomical shape of the conduit or orifice when the expansion device is in the second configuration.

RELATED APPLICATIONS

The present application is a continuation of U.S. Ser. No. 12/618,023,filed Nov. 13, 2009, and now issued as U.S. Pat. No. 8,591,567, which inturn claims priority under 35 U.S.C. §119(e) to U.S. ProvisionalApplication No. 61/117,902 filed Nov. 25, 2008.

FIELD OF THE INVENTION

The present invention concerns embodiments of a system for implanting aprosthetic device, such as an anatomical frame, into an orifice of apatient.

BACKGROUND OF THE DISCLOSURE

When treating certain medical conditions, it is sometimes desirable toexpand a frame or other radially expandable member in an orifice orconduit of a patient's body. For example, expandable tubes called stentsare commonly inserted into a natural conduit of a patient's body andexpanded inside the conduit to hold the conduit in an open position.Such expandable stents can be used to expand, widen, or otherwiseprovide structural support to various conduits of the human body,including, for example, arteries, veins, bile ducts, the esophagus, andthe colon. In other treatment procedures, prosthetic heart valves thatinclude a frame member are implanted into the body at a treatment site(e.g., a heart valve annulus). These prosthetic heart valves can bepositioned in the heart valve annulus by expanding the frame member toroughly the size of the valve annulus.

The expansion of such frames in the body can be performed using anexpansion device, such as a balloon. For example, a method can involvepositioning a frame on a balloon of a balloon catheter, maneuvering theballoon and frame to the treatment site, and inflating the balloon witha fluid to expand the frame to the desired size. Many orifices orconduits in the body, such as the native aortic valve annulus, havenon-cylindrical shapes. Unfortunately, current expansion devices andmethods do not provide a convenient and effective way to expand a frameor other expandable member so that it conforms to a non-cylindricalorifice or conduit.

SUMMARY OF THE INVENTION

In one embodiment an apparatus for radially expanding a prostheticdevice in a conduit or orifice of a human body is provided. Theapparatus comprises an expansion device that has a main axis and anouter mounting surface for mounting the prosthetic device in a crimpedstate thereon. The expansion device can be configured to expand radiallyoutwards from a first configuration to a second configuration to expandthe prosthetic device to an expanded shape having a non-circularcross-sectional profile perpendicular to the main axis of the expansiondevice. The expansion device can be configured to expand the prostheticdevice to generally conform to an anatomical shape of the conduit ororifice. The expansion device can also comprise a plurality ofshape-forming members that have a plurality of external surfaces. Theplurality of external surfaces can form at least a portion of themounting surface of the expansion device. When the expansion device isin the second configuration, the external surfaces of the shape-formingmembers can collectively have a non-circular cross-sectional profileperpendicular to the main axis of the expansion device.

In specific implementations, the plurality of shape-forming membersinclude three or more shape-forming members. In other specificimplementations, the external surfaces of the shape-forming members cancollectively generally conform to the trilobular shape of the aorticvalve annulus when the expansion device is in the second configuration.In other specific implementations, the shape-forming members can beangularly spaced around the main axis.

In specific implementations, the expansion device can further comprise aballoon member that is inflatable from a non-expanded state to anexpanded state. The balloon member can be configured to move theshape-forming members radially outwards from the first configuration tothe second configuration.

In specific implementations, the shape-forming members can be areadhered to an external surface of the balloon member. In other specificimplementations, the shape-forming members can be configured to form asubstantially closed ring shape when the balloon member is in thenon-expanded state.

In specific implementations, the apparatus can further comprise anelongated shaft. One or more linkages can be connected to a distal endof the elongated shaft and to the shape-forming members. In otherspecific implementations, the one or more linkages can be pivotablyconnected to the distal end of the elongated shaft to permit radialexpansion of the shape-forming members. In other specificimplementations, the one or more linkages can be connected to anactuator located at a proximal end portion of the elongated shaft. Theactuator can be configured to radially expand the shape-forming membersvia the one or more linkages.

In specific implementations, the apparatus can comprise a balloon memberand a balloon-restricting member. The balloon member can be configuredto expand from a non-expanded state to an expanded state and theballoon-restricting member can surround at least a portion of theballoon member. The balloon-restricting member can have a plurality ofopenings through which portions of the balloon member extend when theballoon is in the expanded state. The plurality of openings can beconfigured so that when the balloon member is in the expanded state, theexpansion device has an outer profile that is non-circular in crosssection perpendicular to the main axis of the balloon member. Inspecific implementations, the balloon-restricting member can comprise awire frame or a tube.

In another embodiment, a delivery system for delivering a prostheticdevice is provided. The system comprises a prosthetic device and anexpansion device. The prosthetic device comprises a frame member, andthe expansion device has a main axis and an outer mounting surface formounting the prosthetic device in a crimped state thereon. The expansiondevice can be configured to expand radially outwards from a firstconfiguration to a second configuration to expand the prosthetic deviceto an expanded shape having a non-circular cross-sectional profileperpendicular to the main axis of the expansion device. In specificimplementations, the expansion device can comprise a balloon memberhaving a plurality of shape-forming members attached to an externalsurface of the balloon member.

In another embodiment a method of expanding a prosthetic device within aconduit or orifice of a human body is provided. The method comprisesproviding an expansion device that has a main axis and an outer mountingsurface. The method also comprises mounting the prosthetic device on theouter mounting surface of the expansion device. The method alsocomprises expanding the expansion device from a first configuration to asecond configuration to expand the prosthetic device to an expandedshape having a non-circular cross-sectional profile perpendicular to themain axis of the expansion device. In specific implementations, theexpansion device further comprises a balloon member and a plurality ofshape-forming members at least partially surrounding the balloon member,and the step of expanding the expansion device comprises inflating theballoon member. In other specific implementations, when the expansiondevice is in the second configuration, the external surfaces of theshape-forming members collectively define an envelope curve thatgenerally conforms to the anatomical shape of the orifice or conduit.

The foregoing and other features and advantages of the invention willbecome more apparent from the following detailed description, whichproceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an illustration of a portion of aheart.

FIG. 2 is an illustration of a model of a portion of the aortic root.

FIG. 3 is a cross section view taken along line 3-3 of FIG. 2.

FIG. 4 is a perspective view of an expanding device with a frame memberpositioned on the expanding device.

FIG. 5 is an end view of an expanding device with shape-forming members,the device being in an expanded configuration.

FIG. 6 is an end view of an expanding device with shape-forming members,the device being in an unexpanded configuration.

FIG. 7 is a partial cross section view of an illustration of a portionof a heart with an expanding device positioned to expand a frame memberat an orifice of the heart, with the expanding device shown in anunexpanded configuration.

FIG. 8 is a partial cross section view of an illustration of a portionof a heart with an expanding device positioned to expand a frame memberat an orifice of the heart, with the expanding device shown in anexpanded configuration.

FIG. 9 is a perspective view of an expanding device.

FIG. 10A is a bottom view of shape-forming members, shown in an expandedconfiguration without an expanding member.

FIG. 10B is a side view of shape-forming members, shown in an expandedconfiguration without an expanding member.

FIG. 11A is a bottom view of shape-forming members, shown in anunexpanded configuration without an expanding member.

FIG. 11B is a side view of shape-forming members, shown in an unexpandedconfiguration without an expanding member.

FIG. 12A is a bottom view of shape-forming members, shown in an expandedconfiguration without an expanding member.

FIG. 12B is a side view of shape-forming members, shown in an expandedconfiguration without an expanding member.

FIG. 13A is a bottom view of shape-forming members, shown in anunexpanded configuration without an expanding member.

FIG. 13B is a side view of shape-forming members, shown in an unexpandedconfiguration without an expanding member.

FIG. 14A is a top view of an expanded frame member.

FIG. 14B is a perspective view of an expanded frame member.

FIG. 15 is a perspective view of an expanding device.

FIG. 16A is a side view of an expanding device, shown in an expandedconfiguration.

FIG. 16B is a side view of the expanding device of FIG. 16A, shown in anunexpanded configuration.

FIG. 17 is a side view of an expanding device.

FIG. 18A is a side view of another expanding device, shown in anunexpanded configuration.

FIG. 18B is a side view of the expanding device of FIG. 18A, shown in anexpanded configuration.

FIG. 19A is a side view of another expanding device, shown in anunexpanded configuration.

FIG. 19B is a side view of the expanding device of FIG. 18A, shown in anexpanded configuration.

FIG. 20A is a perspective view of an expanding device, shown in anunexpanded configuration.

FIG. 20B is a perspective view of the expanding device of FIG. 20B,shown in an unexpanded configuration.

FIG. 21 is a side view of an expanding device, shown in an expandedconfiguration.

FIG. 22 is a partial cross section view of an expanding devicepositioned at an orifice of a heart and shown in an expandedconfiguration.

FIG. 23A is a side view of an expanding device, shown in an expandedconfiguration.

FIG. 23B is a bottom view of the expanding device of FIG. 23A.

FIG. 24A is a side view of an expanding device, shown in an unexpandedconfiguration.

FIG. 24B is a bottom view of the expanding device of FIG. 24A, shown inan expanded configuration.

FIG. 25A is a side view of an expanding device, shown in an unexpandedconfiguration.

FIG. 25B is a bottom view of the expanding device of FIG. 25A.

FIG. 26A is a side view of the expanding device of FIG. 25A, shown in anexpanded configuration.

FIG. 26B is a bottom view of the expanding device of FIG. 25A, shown inan expanded configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In treating certain medical conditions, it can be necessary or desirableto expand a frame member, a stent, or another type of expandableprosthetic device within an orifice or conduit of the body. However,such orifices and conduits are rarely completely cylindrical and, insome instances, have relatively complex geometries. The followingembodiments provide methods and apparatuses for expanding a frame orother prosthetic member to conform to the anatomical geometry of thesite in the body where the frame or member is being expanded.

FIG. 1 is a cross-sectional view of an illustration of a human heart.Aortic valve 10 includes a valve annulus 12 and, normally, threeleaflets 14 (or cusps) that permit or restrict the flow of blood throughaortic valve 10. Leaflets 12 (or cusps) are passive soft tissuestructures attached to the aortic wall 20 at valve annulus 12 in aregion called the aortic root. Aortic valve 10 is located between theaorta 16 and the left ventricle 18. As the left ventricle 18 contractsduring systole, leaflets 14 are pushed aside, towards aorta wall 20 andblood flows through aortic valve 10 to aorta 16. As the left ventricle18 relaxes during diastole, the pressure in the left ventricle 18 drops,and the leaflets 12 come together, restricting the backflow orregurgitation of blood from the aorta 16 into the left ventricle 18.

FIG. 2 is a model of a portion of the aortic root 22. The threedilations (or sinuses) 24 of the aortic root 22 are a result of threecorresponding recesses (or indentations) in aorta wall 20 adjacentleaflets 14. FIG. 3 is a cross-sectional view of the model of aorticroot 22 shown in FIG. 2, taken at line 3-3. FIG. 3 illustrates theportion of aortic root 22 where the dilations (or sinuses) 24 have amaximum diameter. As seen in FIG. 3, the aortic root 22 (the conduitshown in this embodiment) is not cylindrical (non-circular in crosssection), but rather trilobular.

It can be desirable to expand a stent, frame member, or other expandablemember within the valve annulus of the aortic valve 10 (within theaortic root). Such a member can be, for example, the frame of aprosthetic valve. Alternatively, the expandable member can be a framemember deployed within the aortic annulus that forms a support structureto which a prosthetic valve (or other structure) can be expanded ontoand secured. As used herein, the term “expandable member” means anyprosthetic device that can be radially expanded for deployment in thebody. Conventional delivery devices, such as a conventional ballooncatheter, are configured to expand a prosthetic device to an expandedstate having a circular cross-sectional profile along its length. Thus,a prosthetic valve or stent deployed within the aortic annulus using aconventional balloon catheter may not conform accurately to thetrilobular anatomy of the aortic root.

When the expandable member comprises a first expandable frame memberthat is expanded in an orifice to provide a framework for securing asecond expandable member (such as the stent of a prosthetic heart valve)to the first expandable member, it is desirable to expand the firstexpandable frame member to conform to the shape and configuration of theprosthetic heart valve that is deployed within the first frame member.For example, if the prosthetic heart valve has a trilobular shape, it isdesirable to expand the first expandable member to have the same orsubstantially the same trilobular shape as the prosthetic heart valve.By expanding the first expandable member to the shape of the prostheticheart valve, the frame member and prosthetic valve can be optimallysized and positioned within the valve annulus, and the occurrence ofparavalvular leaks between the frame member and the native annulus aswell as between the frame member and the prosthetic valve can bereduced. Moreover, because the expansion devices disclosed herein can bemodified and/or constructed so that they can expand an expandable memberto conform to the shape of an existing prosthetic heart valve (or otherprosthetic devices), the expansion devices described herein can be usedto expand an expandable member to provide a framework that conforms toexisting, FDA-approved prosthetic surgical heart valves.

FIG. 4 shows an embodiment of an apparatus for expanding an expandablemember to conform to a non-circular anatomical shape of an orifice orconduit of the body. An expander 26 includes a handle 28, a shaft 30,and an expandable balloon member 32. The balloon member 32 has aplurality of longitudinally extending shape-forming members 34 (six, inthis embodiment) that are spaced around the outer surface of the balloonmember 32 at angularly-spaced positions and form a part of the externalstructure of the balloon member 32. Balloon member 32 is shown in aninflated state in FIG. 4. Desirably, shaft 30 comprises a lumen thatextends from the proximal end 36 of the handle 28 to the proximal end ofballoon member 32. The lumen of shaft 30 is in fluid communication withballoon member 32. An inflating device (not shown) can be connected tothe proximal end 36 of the shaft 30, and a fluid that is capable ofinflating the balloon member 32 can be transferred from the inflatingdevice through the lumen to balloon member 32. Balloon inflating devicesare well known and any conventional inflation means can serve to inflateballoon member 32 to expand the expandable member.

A prosthetic device (expandable member) in the form of a frame member,or stent, 70 can be positioned on the shape-forming members 34. Theexpansion of balloon member 32 causes shape-forming members 34 to moveradially outward away from each other, which in turn expand frame member70 to conform to the external shape of shape-forming members 34. Theframe member 70 in the illustrated embodiment is adapted to be implantedwithin the native aortic valve and serves as a support structure forsupporting a prosthetic valve deployed within frame member 70.

The shape-forming members 34 desirably have a cross-section thatgenerally conforms to a non-cylindrical anatomical orifice or conduit inwhich the frame member is to be positioned and expanded. For example,the shape-forming members 34 of FIG. 4 are configured to expand theframe member to conform to the anatomy of the annulus of an aorticvalve. The collective cross section of the shape-forming members 34perpendicular to a main axis, or longitudinal, of the expandable balloonmember (expansion device) is non-cylindrical. The main axis of anexpander or expansion device is defined, for the purposes of thisapplication, as the axis about which the expansion occurs. In this case,since the expansion is a result of the balloon member 32 being inflatedto a larger size, the main axis is the central axis of the balloonmember 32.

In the illustrated example, the shape of the shape-forming members 34 isconfigured so that when the balloon member 32 is expanded, the outersurfaces of the shape-forming members 34 generally conform to the shapeas the aortic root 22 at that location. Since shape-forming members 34are configured to conform to an anatomical geometry of an orifice orconduit, the expanded frame 70, which is formed by contact withshape-forming members 34 during expansion of balloon member 32, alsogenerally conforms to the desired anatomical geometry.

It should be understood that for each embodiment discussed herein, theexpansion device can be configured to expand an expandable member orprosthetic device to generally conform to the non-circular shape of ananatomical orifice or conduit. Alternatively, for each embodimentdiscussed herein, the expansion device can be configured to expand anexpandable member to generally conform to a non-circular shape of asecond prosthetic device (expandable member), which may or may notgenerally conform to a non-circular shape of the anatomical orifice orconduit in which the second prosthetic device is intended to beimplanted.

FIG. 5 is a top end view of the shape-forming members 34 attached toballoon member 32 in an expanded configuration. Shape-forming member 34can have external surfaces 35 that collectively form an outer perimeterof the shape-forming members 34. Although the collective externalsurfaces of the shape-forming members are discontinuous, an outerenvelope curve 37 is defined by the collective external surfaces 35 andthe imaginary lines connecting adjacent surfaces 35 (the dashed lines inFIG. 5). When the balloon 32 is expanded, the envelope curve 37generally conforms to the curvature of the aortic root 22 at the valveannulus, as shown in FIG. 3. The shape-forming members 34 are desirablyformed of a material that is rigid enough to impart the desired shape tothe frame member 70 during expansion.

By placing the shape-forming members 34 at spaced locations around theballoon member 32, the structure can be collapsed to a smaller diameter.For example, as shown in FIG. 6, the shape-forming members 34 cancollapse so that the external surfaces 35 of the shape-forming members34 collectively form a shape that has a smaller outer perimeter. Theability of shape-forming members 34 to collapse to a smaller profilepermits the distal end of expander 26 to enter and exit an orifice orconduit more easily. In addition, each shape-forming member 34 desirablyis sized so that it abuts adjacent shape-forming members 34 when theshape-forming members 34 are in a collapsed (non-expanded)configuration. For example, as shown in FIG. 6, each shape-formingmember 34 is configured to contact adjacent shape-forming members 34 ontwo sides, in order to achieve a smaller profile when in the collapsedconfiguration. Desirably, in the collapsed configuration, theshape-forming members form a closed-ring shape, as shown in FIG. 6. Whenthe balloon 32 is inflated, the shape-forming members 34 move radiallyoutward to the expanded configuration shown in FIG. 5.

FIG. 7 shows an embodiment where expander 26 can be used to expand aframe member 70 to conform to the valve annulus 12 of a heart. Framemember 70 is crimped onto balloon member 32 of expander 26 when theballoon member is in the collapsed configuration (FIG. 6). Frame member70 can be, for example, an expandable frame member (or stent) that isconfigured to be expanded within the orifice of the aortic valve 10, andserves as a support structure onto which a prosthetic valve can besecured. To implant the frame member 70 within the aortic valve 10, thephysician can access the heart by any known surgical techniques. Forexample, access to the aortic valve can be achieved by an uppermini-sternotomy. Alternatively, as discussed in more detail below, theheart can be accessed percutaneously if so desired.

After gaining access to the aorta 16, balloon member 32 (with framemember 70 crimped on balloon member 32 and shape-forming members 34) canbe inserted into the aortic valve annulus 12. Using handle 28, expander26 can be maneuvered until frame member 70 is positioned in the desiredlocation. Once frame member 70 is in the desired position, expander 26can expand frame member 70 by inflation of balloon member 32, trappingvalve leaflets 14 between frame member 70 and valve annulus 12 (and/oraorta wall 20), as depicted in FIG. 8. The expansion of frame member 70can be achieved, for example, by connecting a fluid pressurizing device(or inflating device) to the fluid passageway at the distal end 36 ofshaft 30 and directing fluid through the lumen of shaft 30 and intoballoon member 32.

As the balloon member 32 expands under the force of the fluid from thefluid pressurizing device, the shape-forming members 34 move with theballoon and force the frame member 70 outward. As noted above, theshape-forming members 34 are desirably formed of a relatively rigid (ornon-compressible) material, at least relative to the frame member (orother expandable member). As the balloon member 32 is expanded to thedesired size or pressure, shape-forming members 34 move to the expandedconfiguration (FIG. 5) until they reach the predetermined shape of theconduit or orifice (in this case the shape of the aortic root 22).Because the shape-forming members 34 are relatively rigid (ornon-compressible), as balloon member 32 expands, frame member 70 isforced outward by the shape-forming members 34 and frame member 70 isexpanded to conform generally to the geometry of shape-forming members34. After expanding frame member 70 in the valve annulus, a prostheticheart valve can be deployed within the frame member 70, either bysurgically or percutaneously accessing the heart.

In one application, for example, a prosthetic valve having a generallytrilobular shaped sewing ring (typically used to suture the valve inplace in conventional valve replacement surgery) can be implanted withinthe stent 70. Such sewing ring is positioned to seat against an innersurface of the stent, which has been expanded to have a similartrilobular cross section. In this manner, a tight seal is formed betweenthe stent 70 and the prosthetic valve to minimize paravalvular leaks.The prosthetic valve can have a radially expanded stent connected to thesupport ring that is expanded against the outer stent 70 to anchor theprosthetic valve in place within the outer stent.

FIG. 9 shows another embodiment of an apparatus for expanding aprosthetic device (expandable member) to conform to the anatomical shapeof an orifice or conduit of the body having a non-circularcross-sectional profile. The expander 26 of FIG. 9 is similar to theexpander shown in FIG. 4, except that handle 28 can be movablelongitudinally relative to shaft 30. In order to fix the position ofhandle 28 relative to shaft 30, a position lock 44 is provided. Bydepressing the position lock 44, the position of the handle can belocked and unlocked relative to the shaft 30. Desirably, handle 28 isflexible and can flex with shaft 30 to permit the expander 26 to be moreeasily maneuvered. Also, handle 28 desirably provides a comfortablegripping surface for the physician. Except for the differences notedabove and shown in FIG. 9, the expander shown in FIG. 9 functions insubstantially the same manner as the expander shown in FIG. 4.

Shape-forming members, such as those discussed above, can be formed in avariety of ways. In one embodiment, the shape-forming members 34 can beformed by constructing a plurality of shape-forming members to conformto a model, such as a computer-aided design (CAD) model, of the conduitor orifice into which the frame or expandable member is to bepositioned. In creating shape-forming members, a CAD model of thenon-cylindrical orifice or conduit can be constructed (such as theaortic root model of FIG. 3) and the relevant portion of the CAD modelcan be selected and sectioned. Certain sections can be selected andretained to maintain the general outer shape of the modeled conduit ororifice, and the remaining sections can be discarded. In this manner,separate and distinct pie-shaped pieces or sections of the shape-formingmembers can have discontinuous (spaced-apart) external surfaces thatcollectively define an envelope curve that approximates the shape of theanatomical orifice or conduit when the balloon member is expanded, whilepermitting the shape-forming members to achieve a smaller diameter (orprofile) when the balloon member is deflated.

For example, FIGS. 10A and 10B show a plurality of shape-forming members34 in an expanded configuration (without the balloon member). The outerenvelope of the expanded configuration in plan view substantially formsthe shape of the conduit or orifice that is to be expanded (e.g., thevalve annulus). Again, the shape-forming members have external surfacesthat collectively form an outer envelope having a non-cylindrical shapeperpendicular to a main axis of the expansion device. Shape-formingmembers 34 are desirably shaped to mate with the valve annulus, andtissue above the valve annulus in the aorta. Accordingly, in addition tohaving a shape that is non-cylindrical (when viewed from above, such asin FIG. 5), the shape-forming members can have a shape that varies alongthe length of the shape-forming members. For example, an expandeddiameter 54 defined by the flared upper portions 50 of shape-formingmembers 34 (i.e., the portions that extend into the aorta) can be about32 mm (or 1.260 inches), and an expanded diameter 56 defined by thelower portions 52 of shape-forming members 34 (i.e., the portion thatextends into the left ventricle) can be about 23 mm (or 0.906 inches).In this manner, the expanded frame member 70 is formed with an enlargedupper portion that tapers to a smaller diameter lower portion to betterconform to the aortic annulus and the aortic root immediately adjacentthe annulus.

As noted above, the upper portions 50 of shape forming members 34 arepreferably non-circular. In one application, upper portions 50 can begenerally trilobular in cross section (perpendicular to a main axis ofthe expansion device) to generally conform to the shape of the aorticvalve annulus. Lower portions 52 can be non-circular as well; however,it can be desirable to form lower portions 52 so that they are generallycircular, as shown in FIGS. 10A and 10B. In addition, if desired,shape-forming members 34 can be formed with intermediate portions 53that have a different diameter than upper and lower portions 50, 52. Asshown in FIGS. 10-13, intermediate portions 53 can have a diameter thatis smaller than the diameters of the upper portions 50 and lowerportions 52. The intermediate portions 53, when expanded, can define anouter envelope that has a trilobular shape, similar to upper portions50. In alternative embodiments, the intermediate portions 53, whenexpanded, can define an outer envelope that is substantially circular incross section. To the extent that a portion of the expanded device isnot circular in cross section (such as diameter of upper portions 50),the diameters discussed above are determined by taking the largestdimensions between opposing points on the outer envelope curve formed bythe collective surfaces of the shape-forming members at that particulararea or location.

In addition, if desirable, the transition between the lower portions 52and the intermediate portions 53 can include lip portions 55. Byconfiguring the shape-forming members 34 with lip portions 55, theshape-forming members can better hold a prosthetic device in place onthe expansion device. For example, as shown in FIG. 4, lip portions 55are positioned to abut an adjacent area of the prosthetic device (framemember 70), thereby restricting movement of the prosthetic device (framemember 70) in the distal direction during positioning and expansion ofthe expansion device.

Because the shape-forming members 34 have gaps or discontinuities intheir expanded configuration, the shape-forming members 34 can have asmaller profile (or diameter) when the balloon member is deflated. FIGS.11A and 11B show a plurality of shape-forming members 34 in anon-expanded (collapsed) configuration. In this configuration, anon-expanded diameter 58 defined by the upper portions 50 ofshape-forming members 34 (i.e., the portions that extend into the aorta)can be about 19 mm (or 0.74803 inches), and an non-expanded diameter 60defined by the lower portions 52 of shape-forming members 34 (i.e., theportions that extend into the left ventricle) can be about 11.25 mm (or0.5118 inches). Accordingly, the non-expanded configuration ofshape-forming members 34 can be smaller than the expanded configurationof shape-forming members 34.

Shape-forming members 34 can be configured to conform to a variety ofshapes and geometries. The shape and/or geometry of shape-formingmembers 34 can be configured to conform to these shapes by, for example,forming a model of the conduit or orifice (such as is shown in FIGS. 2and 3) and selecting portions of the external structure of that model toform the basis for the shape-forming members of an expanding device.

The number of shape-forming members 34 can vary. In the embodimentsdiscussed above, there are six shape-forming members; however, there canbe more or less than six members. For example, FIGS. 12A, 12B, 13A, and13B show an embodiment with three shape-forming members 34 that has atrilobular cross-sectional profile.

The expanded and non-expanded diameters of shape-forming members shownin FIGS. 12A, 12B, 13A, and 13B can have diameters that are about thesame as the diameters of the six member embodiment of FIGS. 10A, 10B,11A, and 11B. For example, FIG. 12A shows an embodiment having aplurality of shape-forming members (three, in this embodiment) where anexpanded diameter 62 defined by the upper portions 50 of shape-formingmembers 34 (i.e., the portions that extend into the aorta) can be about32 mm (or 1.260 inches), and an expanded diameter 64 defined by lowerportions 52 of shape-forming members 34 (i.e., the portions that extendinto the left ventricle) can be about 23 mm (or 0.906 inches). FIGS. 13Aand 13B show a plurality of shape-forming members 34 in a non-expanded(collapsed) configuration. In this configuration, a non-expandeddiameter 66 defined by the upper portions 50 of shape-forming members 34(i.e., the portions that extend into the aorta) can be about 19 mm (or0.74803 inches), and a non-expanded diameter 68 defined by lowerportions 52 of shape-forming members 34 (i.e., the portions that extendinto the left ventricle) can be about 11.25 mm (or 0.5118 inches). Itshould be noted that, as discussed above, although the dimensions aboveare given with regard to a circular diameter, the actual shape definedby the shape-forming members is non-circular. The discussion of theinner and outer diameters is included merely for convenience inillustrating the relative expanded and non-expanded profiles of thedevices.

Of course, the size of the shape-forming members can vary and the arclength of the shape-forming members can be made larger or smaller toreduce or increase, respectively, the number of shape-forming membersthat are used. In addition, the spaces or gaps between the shape-formingmembers can be increased or decreased depending on the particularrequirements of the desired application.

Shape-forming members 34 can be adhered to the balloon member 32 (orother expansion device) using adhesives and/or mechanical fasteners. Inlieu of or in addition to using an adhesive and/or fastener to attachthe shape-forming members to the balloon, it may be desirable to apply asleeve member that forms a layer (or overcoat) of material over at leasta portion of the external surfaces of the shape-forming members and theballoon. The layer can be formed of a variety of materials, including,for example, silicone or other similar materials. If desirable, thesleeve can be formed by dip coating the balloon and shape-formingmembers 34 in a liquefied material, such as liquefied silicone or othersimilar materials. The overcoat layer can help the shape-forming membersadhere to the balloon member, as well as serve as a protective materialby reducing or eliminating any hard edges or points on the shape-formingmembers.

As discussed above, the expandable member can be a frame member that canbe expanded to fit the aortic annulus, onto which a separate prostheticvalve can be secured. As shown in FIGS. 14A and 14B and as discussed inmore detail herein, frame member 70 can be expanded as shown to conformto the trilobular geometry of the aortic root 22. Frame 70 can becrimped to a smaller profile prior to expansion within the body. Bycrimping frame 70 to a smaller profile, it can be more easily movedthrough the body into position at the aortic valve annulus (or someother desired location).

FIG. 15 shows another embodiment of an apparatus for expanding anexpandable member to conform to the anatomical shape of an orifice orconduit of the body. Expansion of an expandable member (e.g., frame 70discussed above) can be achieved by means other than an inflatableballoon member. As shown in FIG. 15, expander 72 does not utilize aballoon member to cause the expansion of an expandable member. Rather,expander 72 has a plurality of shape-forming members 74 that can beforced to move radially outward or inward by applying a force along theaxis 86 of the expander 72. In particular, shape-forming members 74 areattached to a plurality of linkages or arms, including distal arms 76and proximal arms 88. Distal arms 76 are pivotably attached to an innershaft 78. Proximal arms 88 are pivotably coupled to inner shaft 78 andto an outer shaft 82. Because proximal arms 88 are pivotably coupled toboth inner shaft 78 and outer shaft 82 (but not about the same point asshown in FIG. 16A), relative movement of the two shafts is effective topivot shape-forming members 74 radially outward, as discussed in moredetail below.

Expander 72 also has a handle portion 80 connected to the outer shaft 82at a proximal end of expander 72. Handle portion 80 can have an actuatorthat is configured to move shape-forming members 74 via the arms 76, 88.For example, the actuator can be a sliding mechanism 81 that is attachedto inner shaft 78 at its proximal end. By moving sliding mechanism 81axially in the proximal or distal direction, the relative positions ofthe outer shaft 82 and inner shaft 78 can be adjusted and theshape-forming members can be radially expanded. For example, by movingsliding mechanism 81 (and, by extension, inner shaft 78) in the proximaldirection, as designated by arrow 84, proximal arms 88 are forced topivot toward the distal end of the expander and radially inwardly fromthe expanded configuration shown in FIG. 15 towards an unexpandedconfiguration. On the other hand, by moving sliding mechanism 81 in thedistal direction (the opposite direction of arrow 84), proximal arms 88are forced toward the proximal end of the expander and radially outwardto move the shape-forming members 74 radially outward to the expandedconfiguration shown in FIG. 15.

Arms 76 and 88 desirably are pivotably coupled to shape-forming members74 so that the shape-forming members 74 remain substantially parallel tothe main axis of the expander while moving from the unexpandedconfiguration to the expanded configuration and vice versa. Thus,external surfaces of shape-forming members that are substantiallyparallel to the main axis of the expander in the non-expandedconfiguration are also substantially parallel to the main axis of theexpander in the expanded configuration, and at each position between theexpanded and unexpanded position.

Referring now to FIGS. 16A and 16B, each shape-forming member 74 ispivotably coupled to a distal arm 76 and to a proximal arm 88. Each arm76 is pivotably coupled at one end to inner shaft 78 at a first pivotjoint 79 and at its other end to shape-forming member 74 at a secondpivot joint 83. Each arm 88 is pivotably coupled to a first pivot point85 on inner shaft 78, a second pivot point 87 on the outer shaft 82, anda third pivot point 89 on a respective shape-forming member 74. Thesecond pivot point 87 is offset from the first pivot point 85, and islocated at a point between the first pivot point 85 and the third pivotpoint 89. By moving sliding mechanism 81 (as shown in FIG. 15)proximally in the direction of arrow 84, the movement of inner shaft 78relative to outer shaft 82 causes proximal arms 88 to pivot inward oninner shaft 78, moving the shape-forming members 74 to the collapsedconfiguration shown in FIG. 16B. Each shape-forming member 74 can alsobe formed with an opening (or slot) 89 to receive a portion of thedistal arms 76 as the shape-forming members 74 collapse to a smallercross-sectional profile. As shown in FIG. 16B, as shape-forming members74 fully collapse to their smallest cross-sectional profile, distal arms76 extend at least partially into openings 89. If desired, eachshape-forming members 74 can include a lip portion 91 and anintermediate portion 93. Lip portions 91 and intermediate portions 93can be configured as discussed above with regard to FIGS. 10-13.

The shape-forming members 74 have a non-cylindrical and non-circularcross-sectional profile perpendicular to the main axis of the expander72, with the main axis being the axis about which the shape-formingmembers expand. Shape-forming members 74 can be formed of sections thatapproximate the outer shape of the conduit or orifice into which theframe member or other expandable member is to be position (e.g., theaortic annulus). The plurality of shape-forming members can be formed,as discussed above, with any number of different sections or members.FIG. 15 shows an expander with three shape-forming members; however,there could be as few as two members or there can be more than threemembers. In addition, as with the expanders discussed above, thecollapsed profile of expander 72 is smaller than its expanded profile,permitting expander 72 to more easily enter and exit the body orifice orconduit before and after expansion of the frame member or otherexpandable member.

FIG. 17 shows another embodiment of a mechanical expander. Expander 90has a moveable handle portion 92 and a shaft portion 94. Shaft portion94 extends through handle portion 92 and distal arms 98 are pivotablyconnected to a distal end of shaft portion 94. Proximal arms 100 arepivotably connected to a distal end 96 of handle portion 94. Distal arms98 and proximal arms 100 are pivotably coupled to shape-forming members102. By moving handle portion 92 relative to shaft portion 94,shape-forming members 102 can be moved from a first configuration (e.g.,an unexpanded configuration) to a second configuration (e.g., anexpanded configuration) and vice versa. For example, by holding shaftportion 94 in a fixed position and moving handle portion 92longitudinally in the direction of the arrow 104, the distal end 96 ofhandle portion 92 causes proximal arms 100 to move radially outward toexpand a prosthetic device (not shown) mounted on the shape-formingmembers. The outward movement of proximal arms 100 forces shape-formingmembers 102 to move radially outward. Because distal arms 98 arepivotably coupled to shaft portion 94, the movement of proximal arms 100radially outward also forces distal arms 98 to move radially outwards.

To collapse the expander 90 and return shape-forming members 102 to anunexpanded configuration, handle portion 92 can be moved longitudinallyin the direction opposite arrow 104. By moving handle portion 92proximally, proximal arms 100 are moved radially inward, which causesshape-forming members 102 to return to an unexpanded configuration.

When the handle portion 92 is moved to a position of maximum expansion,both the proximal and distal arms can extend radially at about 90degrees from the axis of the shaft portion 94. In its expandedconfiguration, the expander 90 has a larger diameter than it does in itsnon-expanded (or collapsed) configuration.

FIGS. 18A and 18B show another embodiment of a mechanical expander. Anexpander 110 includes a handle portion 112 and a plunger portion, orshaft, 114. The handle portion 112 can have one or more finger holes 116that allow a user to hold handle portion 112 comfortably. The distal endof handle portion 112 has a plurality of flexible finger portions 118,which are connected to the handle portion 112 but separated from oneanother via one or more slits 120. Handle portion 112 is configured witha passageway or bore extending longitudinally through handle portion112. Plunger portion 114 is configured to be moveable longitudinallythrough the bore between a first position (FIG. 18A) and a secondposition (FIG. 18B). By moving the plunger portion from the firstposition (FIG. 18A) to the second position (FIG. 18B), the plungerportion 114 can cause finger portions 118 to move radially outward.

Finger portions 118 function as shape-forming members so that radialexpansion of finger portions 118 is effective to expand a frame memberor other expandable member that is disposed on a distal end 125 of thefinger portions 118. Desirably, the distal end portion 125 of the fingerportions 118 is tapered to a smaller diameter. In operation, plungerportion 114 (including an enlarged cylindrical portion 122 at the distalend of the plunger) can be moved distally through the handle portion 112from the first position to the second position. As the cylindricalportion 122 extends into the tapered section of the finger portions 118,the larger diameter of the cylindrical portion 122 forces the taperedsection of the finger portions 118 to move radially outward. The radialexpansion of the finger portions 118 operates to force the expansion ofa frame member that is disposed (or positioned) on the distal end of thefinger portions 118.

After the frame member is expanded by the movement of the plungerportion 114 into the opening of handle portion 112, the expander 110 canbe collapsed by moving the plunger portion 114 longitudinally in theproximal direction. As the plunger portion 114 moves out of the taperedsection of the handle portion 112, the finger portions 118 move radiallyinward under their own resiliency and the expander can return to itscollapsed or unexpanded configuration.

The outer surface of the finger portions 118 that mount the prostheticdevice can be configured to conform to an anatomical shape of an orificeor conduit of the body. For example, as shown in FIG. 18B, in itsexpanded configuration, the finger portions 118 of the handle portion112 have a smaller diameter at a location nearer the distal end of thefinger portions 118 and have a larger diameter at the portion justproximal to the tapered portion. In this manner, finger portions 118form a non-circular outer envelope curve as discussed above with regardto other embodiments.

FIGS. 19A and 19B illustrate another plunger-type mechanical expander.Expander 130 has a handle portion 132 and a plunger portion 135. Thegeneral operation of expander 130 is similar to the expander shown inFIGS. 18A and 18B, except that the relative positions of the handleportion 132 and the plunger portion 135 are changed by rotating the twoportions relative to each other.

As in the embodiment described with reference to FIGS. 18A and 18B,plunger portion 135 has an elongated shaft 137 that extends through anopening in handle portion 132. However, unlike FIGS. 18A and 18B, handleportion 132 has an internally threaded portion 133 and shaft 137 has anexternally threaded portion 136. Internally threaded portion 133 ofhandle portion 132 mates with the externally threaded portion 136 ofshaft 137 and, when plunger portion 135 is rotated about the main axis139 of the expander, plunger portion 135 moves longitudinally relativeto handle portion 132. By rotating the plunger portion 135, for example,in a clockwise direction (about the axis of the handle and plungerportions) the plunger portion 135 moves further into the opening ofhandle portion 132 in the distal direction. By rotating the plungerportion 135 in a counter-clockwise direction (about the axis of thehandle and plunger portions) the plunger portion 135 moves out of theopening of handle portion 132 in the proximal direction.

As in the embodiment shown in FIGS. 18A and 18B, the distal end portion145 of the handle portion 132 has flexible finger portions 140 that areseparated by slits 142. A radially expandable frame member or otherexpandable member can be positioned on a tapered (or narrowed) outersurface of distal end portion 145 of handle portion 132 in a crimped orcollapsed state. When plunger portion 135 is rotated clockwise, anenlarged cylindrical portion 138 of the shaft 137 extends further intothe opening of the handle portion 132 and eventually moves into thetapered portion of handle portion 132. Once the enlarged cylindricalportion 138 extends into the tapered portion of the finger portions 140,the finger portions 140 are forced radially outward. The force of theradial expansion of the finger portions 140 causes the expansion of theframe member positioned on the distal end portion 145 of the handleportion 132.

FIGS. 20A and 20B show another embodiment of a mechanical expander in acollapsed state (FIG. 20A) and an expanded state (FIG. 20B). As shown inFIG. 20A, expander 150 can include a wedge member 152 that can movelongitudinally along axis 154. A plurality of shape-forming members 156can be slidably connected to wedge member 152 and configured such thatlongitudinal movement of wedge member 152 forces the shape-formingmembers radially outwards or radially inward, depending on the directionof movement of wedge member 152.

Shape-forming members 156 can also be connected to a cap member 158 atthe distal end of the expander. Wedge member 152 is fixedly connected tothe distal end of a main shaft 160 and can be moved longitudinally alongaxis 154 by moving shaft 160. Shaft 160 desirably has a handle portion(not shown) at the proximal end of shaft 160 to facilitate movement ofshaft 160 relative to an inner shaft 161. Inner shaft 161 extendsthrough main shaft 160 and is connected at its distal end to cap member158. Main shaft 160 is moveable longitudinally relative to the innershaft 161 to move wedge member 152 relative to shape-forming members 156and cap member 158. Wedge member 152 and/or cap member 158 can haveslots 162 formed in an outer surface thereof. Shape-forming members 156can be mounted to wedge member 152 and/or cap member 158 via projectionsformed on the inner surfaces of the shape-forming members and whichextend into slots 162.

The projections can extend from shape-forming members 156 into slots162, thereby securing shape-forming members 156 to the wedge member 152and/or cap member 158. The projections desirably are configured topermit shape-forming members 156 to move relative to the wedge member152 and the cap member 158, but prevent shape-forming members 156 fromseparating from wedge member 152 and/or cap member 158. In operation, asshaft 160 is moved distally (in the direction of axis arrow 154), wedgemember 152 slides distally, moving shape-forming members 156 radiallyoutward from the collapsed state (FIG. 20A) to the expanded state (FIG.20B). At the same time shape-forming members 156 move distally along theouter surface of cap member 158.

FIG. 21 shows another embodiment of an expander. Expander 170 is ahybrid of a balloon expander and a mechanical expander. As in theembodiment shown in FIG. 4, expander 170 includes a handle 172, a shaft174, and an expandable balloon member 176. In addition, shape-formingmembers 178 surround balloon member 176 as part of an external frame 180that is not directly attached to balloon member 176. The external framecomprises a proximal portion 177 (proximal to the balloon member 176)mounted on the distal end portion of shaft 174, elongated arms 179 thatextend from the proximal portion 177, and shape-forming members 178 thatare coupled to the distal ends of arms 179 and which at least partiallysurround the balloon member 176. Any number of arms can be used tosecure the shape-forming members to the proximal portion 177 of theexternal frame 180; however, desirably, there are at least two arms anddesirably, the number of arms corresponds to the number of shape-formingmembers 178.

As in the embodiment of FIG. 4, shaft 174 desirably comprises a lumenthat extends from the proximal end of the handle 184 to the proximal endof balloon member 176. The lumen of shaft 174 is in fluid communicationwith balloon member 176. An inflating device (not shown) can beconnected to the proximal end 184 of the shaft 174 and a fluid that iscapable of inflating the balloon member 176 can be transferred from theinflating device through the fluid passageway to balloon member 176 viathe lumen of shaft 174. Balloon inflating devices are well known and anyconventional inflation means can serve to inflate balloon member 176 toexpand the shape-forming members 178.

In addition to having an external frame 180, the expander 170 caninclude one or more locking members 182 that connect the shape-formingmembers 178 to one another. The locking member 182 at least partiallysurrounds balloon 176 and can have a structure that permits theshape-forming members to expand radially away from one another, butrestricts movement of the shape-forming back towards an unexpandedconfiguration.

As seen in FIG. 21, locking members 182 can have grooves that lock (orhold) the expander 170 in any of a plurality of expanded positions. Inparticular, the grooves (or teeth) can mate with opposing grooves (orteeth) on the inside of shape-forming members 178, permitting theshape-forming members 178 to move away from one another, while at thesame time preventing them from collapsing back towards each other afterthe balloon member 176 is deflated. As the balloon member 176 inflates,the radial force from the expanding balloon member 176 forces theshape-forming members 178 to move radially outward and the lockingmembers 182 hold the shape-forming members 178 in the expanded position.If desired, a release mechanism can be provided. For example, a wire canbe provided that releases the locking members from their locked position(e.g., by pulling the grooves or teeth radially inward). The wire (orrelease mechanism) can extend from the locking member through the armsand up the shaft 174, and can be accessible at the handle 172.

For example, as shown in FIG. 22, a balloon member 190 can be configuredwith a center longitudinal portion and a first portion 192 that extendsinto the aorta 16 and a second portion 194 that extends into the leftventricle 18. The first and second portions 192, 194 can have a largerdiameter than the center portion. Second portion 194 of balloon member190 can be introduced into the left ventricle 18 in a collapsed(non-expanded) state so that second portion 194 can easily pass throughthe annulus 12. Once properly position within the annulus 12, balloonmember 190 can be inflated (expanded) in the manner discussed above withregard to other embodiments. In operation, a frame or other expandablemember can be crimped on balloon member 190 (or otherwise positioned atthe treatment site for expansion). Balloon member 190 can haveshape-forming members (not shown in FIG. 22, but as described in detailherein) positioned on the balloon member 190 beneath the location of thecrimped, mounted valve.

Desirably, the frame member can be positioned so that it will contactboth first and second portions of balloon member 190 during expansion.After positioning (or mounting) the frame member on the balloon member190 and then positioning the frame member and balloon member at thedeployment location, the balloon member 190 can be inflated as describedabove and the frame member can be expanded to the desired shape.

The inflation of balloon member 190 can be achieved in a single stage orin multiple stages. A single stage inflation can be achieved by having asingle lumen that inflates both first portion 192 and second portion194. Once the balloon member 190 is in position, fluid can pass througha lumen in a balloon catheter 196 (or other shaft that has a lumen thatis in fluid connection with the balloon member and the fluidpressurizing device) to the balloon member 190, thereby inflating firstportion 192 and second portion 194 substantially simultaneously.

Alternatively, the inflation of balloon member 190 can be achieved intwo stages. Separate lumens (not shown) can be connected to firstportion 192 and second portion 194 to allow for the inflation of firstportion 192 and second portion 194 to be separately achieved. Expandingthe portion of the balloon member 190 that is in the ventricle areafirst can provide better visibility for proper anatomical placement ofthe second portion 194 of balloon member 190. That is, it may bedesirable to inflate second portion 194 on the left ventricle 18 side ofthe annulus 12 prior to inflating first portion 192. After secondportion 194 is inflated, first portion 192 can be inflated on the aorta16 side of the annulus 12.

FIGS. 23A and 23B show another embodiment in which an expanding memberis constructed so that it can expand a frame member or other expandablemember to conform to a particular anatomical shape having a non-circularcross-sectional profile. In this embodiment, a balloon member 200 isconstructed with three lobes 202 that are shaped to conform to theaortic root at the aortic valve annulus, as shown in FIGS. 2 and 3above. Balloon member 200 can expand a frame member (such as framemember 70 shown in FIGS. 14A and 14B) to have a trilobular shape toconform to the natural anatomical configuration of the aortic root atthe aortic valve annulus.

Balloon member 200 can be formed with three distinct chambers that eachform one of the three lobes 202. Each of the three lobes 202 can bepressurized via a lumen in a balloon catheter shaft 204 (or other shaftthat has a lumen that is in fluid connection with the balloon member andthe fluid pressurizing device). Three separate lumens can be connectedto each of lobes 202. Desirably, however, a single lumen is connected tothe three lobes. In this manner, each lobe 202 is connected to the samefluid supply, which permits quick and uniform expansion of the threelobes 202. When balloon member 200 is fully inflated, the lobes 202collectively form a trilobular cross-sectional profile (as best shown inFIG. 23B) that generally conforms to the anatomical shape of the aorticroot at the valve annulus.

Balloon member 200 can be formed with lobes 202 by molding the balloonmember 200 so that it has the desired shape. Alternatively, threeseparate balloon members can be heat sealed together to form thetrilobular shape of balloon member 200. The three separate balloonmembers can be connected to the same fluid source at a proximal end ofthe balloon member 200 in a manner that is similar to the constructionof air coils on a floatation raft for a swimming pool.

The embodiment of FIG. 22 can be combined with the embodiment shown inFIGS. 23A and 23B to form an expansion device with four sections. Suchan expansion device can have the three section trilobular configuration(as shown in FIG. 23A) forming first portion 192 (as described abovewith regard to FIG. 22) and the second portion 194 being formed as shownin FIG. 22. With such a construction, second portion 194 can expand theportion of a frame member that is in left ventricle and the trilobularconfiguration of first portion 192 can expand the portion of a framemember that is in the aorta. The portion of frame member that isexpanded by the trilobular configuration of first portion 192 isexpanded to have a similar trilobular shape that generally conforms tothe trilobular shape of the aortic root.

FIGS. 24A and 24B show another embodiment in which an expansion deviceis constructed so that it can expand a frame member or other expandablemember to conform to a particular anatomical shape having a non-circularcross-sectional profile. In this embodiment, an expansion device 210includes a balloon member 212 and a shape-forming member(balloon-restricting member) 214. Shape-forming member 214 compriseswire members that restrain the expansion of balloon member 212 and causethe balloon member to assume a desired non-circular cross section whenexpanded. The shape-forming member 214 can be formed in a variety ofconfigurations. FIG. 24A shows a shape-forming member comprising threewires 214 positioned about the balloon member such that the balloonmember, when expanded, is restrained where the balloon member contactseach wire 214. By restraining the expansion of balloon member 212 inthis manner, the expansion device 210 will form a trilobular shape whenthe balloon member 212 is fully expanded.

FIG. 24A shows balloon member 212 in a deflated state inside ofshape-forming member 214. When balloon member 212 is expanded insideshape-forming member 214, the three wire members of shape-forming member204 restrict the expansion of the balloon member 212 at the location ofthe wire members, but permit the expansion of the balloon member 212 inthe areas between the wire members. Accordingly, as shown in FIG. 24B,the balloon member 212 expands into a trilobular configuration.Consequently, expansion device 210 can expand a frame member (such asframe member 70 shown in FIGS. 14A and 14B) to have a trilobular shapethat generally conforms to the natural anatomical configuration of theaortic root at the aortic valve annulus.

FIGS. 25A, 25B, 26A, and 26B show another embodiment in which anexpansion device is constructed so that it can expand a frame member orother expandable member to conform to a particular anatomical shape. Inthis embodiment, an expansion device 220 includes a balloon member 224and a shape-forming member (balloon-restricting member) 226.Shape-forming member 226 can be a relatively rigid member (at leastcompared to balloon member 224) that has one or more openings 222. Theembodiment shown in FIG. 26A has three openings spaced approximately 120degrees apart (as measured from the center of each opening). Byconstructing shape-forming member 226 with three openings in thismanner, when balloon member 224 is inflated within shape-forming member226, balloon member 224 extends out of shape-forming member 226 at thelocations of the openings. As shown in FIG. 26A, after inflation ofballoon member 224, the resulting shape of expansion device 220 at theballoon member is trilobular.

FIG. 25A shows balloon member 224 in a deflated state inside ofshape-forming member 226. When balloon member 224 is expanded insideshape-forming member 226, shape-forming member 226 restricts theexpansion of balloon member 224 except at the locations of the openings.Accordingly, as shown in FIGS. 26A and 26B, balloon member 224 expandsinto a trilobular configuration. Consequently, expansion device 220 canexpand a frame member (such as frame member 70 shown in FIGS. 14A and14B) to have a trilobular shape that generally conforms to the naturalanatomical configuration of the aortic root at the aortic valve annulus.

In addition, it should be noted that although the embodiments discussedabove depict methods for expanding frames or other expandable membersusing surgical methods to access an orifice or conduit of the body, suchexpanders could also be used in procedures where access to the orificeor conduit is achieved through the patient's vasculature in apercutaneous delivery approach (e.g., via a femoral artery). Forexample, as shown in FIG. 6, a balloon member 32 with shape-formingmembers 34 can be collapsed down to a smaller diameter. The ability tocollapse the balloon member 32 and shape-forming members 34 to a smallerdiameter enables the device to be passed through a patient's vasculatureto arrive at a treatment site. Accordingly, the expanders describedabove could be combined with a conventional balloon catheter that issized to be passed through the vasculature of a patient (using aseparate guide catheter if desired) to reach an orifice or conduit inthe body in which it is desired to expand a frame member or otherexpandable member.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

We claim:
 1. A mechanical apparatus for radially expanding a prostheticdevice in a conduit or orifice of a human body, the apparatuscomprising: an expansion device having a main axis and an outer mountingsurface having a first configuration for mounting the prosthetic devicein a crimped state thereon, the expansion device comprising a pluralityof rigid shape-forming members angularly arranged around the main axisand each having an external surface, wherein the combination of theexternal surfaces defines a longitudinal profile for the outer mountingsurface that varies along its axial length in the first configuration,and an axially moveable shaft configured to cam the shape-formingmembers radially outwards and convert the outer mounting surface fromthe first configuration to a larger second configuration and expand theprosthetic device to an expanded state having a longitudinal profilethat varies along its axial length and conforms to the shape of theconduit or orifice.
 2. The apparatus of claim 1, wherein in the expandedstate a distal end of the prosthetic device is radially larger than aproximal end.
 3. The apparatus of claim 1, wherein the longitudinalprofile has a first end, a second end radially smaller than the firstend, and an intermediate portion with a diameter that is radiallysmaller than both the first and second ends.
 4. The apparatus of claim3, wherein the external surfaces of the shape-forming memberscollectively define a trilobular shape in the second configuration atthe first end, and a substantially circular cross-section in theintermediate portion.
 5. The apparatus of claim 1, wherein the axiallymoveable shaft comprises concentric inner and outer shafts, and theexpansion device comprises a distal wedge member to which the innershaft connects and a proximal wedge member to which the outer shaftconnects, wherein the wedge members are arranged to be axially displacedtoward one another and cam outward the shape-forming members uponrelative movement of the inner and outer shafts.
 6. The apparatus ofclaim 5, wherein at least one of the inner and outer shafts has athreaded portion and is axially displaced by relative rotation of amating threaded member.
 7. The apparatus of claim 5, wherein each of thewedge members includes axial slots therethrough and the shape-formingmembers include projections formed on inner surfaces thereof whichextend into the slots.
 8. The apparatus of claim 1, wherein the axiallymoveable shaft comprises a plunger that extends distally in between theshape-forming members which are flexible and cam apart from impositionof the plunger therebetween.
 9. The apparatus of claim 8, wherein theplunger has a threaded portion and is axially displaced by relativerotation within a mating threaded handle.
 10. The apparatus of claim 1,wherein the expansion device comprises one or more hinged linkagesconnected to a distal end of the axially-movable shaft and to theshape-forming members.
 11. The apparatus of claim 1, wherein each of theshape-forming members forms a pie-shaped cross-sectional configurationwith an external surface that defines a portion of the outer mountingsurface and two generally radially oriented sides that contact theadjacent shape-forming members′ sides in the first configuration.
 12. Amechanical apparatus for radially expanding a prosthetic device in aconduit or orifice of a human body, the apparatus comprising anexpansion device having a main axis and an outer mounting surface havinga first configuration for mounting the prosthetic device in a crimpedstate thereon, wherein the expansion device comprises a plurality ofrigid shape-forming members angularly arranged around the main axis andeach having an external surface, wherein the combination of the externalsurfaces defines a longitudinal profile for the outer mounting surfacethat varies along its axial length in the first configuration, and anaxially moveable shaft configured to displace the shape-forming membersradially outwards and convert the outer mounting surface from the firstconfiguration to a larger second configuration and expand the prostheticdevice to an expanded state having a longitudinal profile that variesalong its axial length and conforms to the shape of the conduit ororifice, wherein in the first configuration, the shape-forming membersare in contact with each other, and in the second configuration theshape-forming members are spaced apart from each other and the pluralityof external surfaces define a longitudinal profile that varies along itsaxial length.
 13. The apparatus of claim 12, wherein each of theshape-forming members forms a pie-shaped cross-sectional configurationwith an external surface that defines a portion of the outer mountingsurface and two generally radially oriented sides that contact theadjacent shape-forming members sides in the first configuration.
 14. Theapparatus of claim 12, wherein the longitudinal profile has a first end,a second end radially smaller than the first end, and an intermediateportion with a diameter that is radially smaller than both the first andsecond ends.
 15. The apparatus of claim 12, wherein in the expandedstate a distal end of the prosthetic device is radially larger than aproximal end.
 16. The apparatus of claim 12, wherein the axiallymoveable shaft comprises concentric inner and outer shafts, and theexpansion device comprises a distal wedge member to which the innershaft connects and a proximal wedge member to which the outer shaftconnects, wherein the wedge members are arranged to be axially displacedtoward one another and force outward the shape-forming members uponrelative movement of the inner and outer shafts.
 17. The apparatus ofclaim 16, wherein at least one of the inner and outer shafts has athreaded portion and is axially displaced by relative rotation of amating threaded member.
 18. The apparatus of claim 16, wherein each ofthe wedge members includes axial slots therethrough and theshape-forming members include projections formed on inner surfacesthereof which extend into the slots.
 19. The apparatus of claim 12,wherein the axially moveable shaft comprises a plunger that extendsdistally in between the shape-forming members which are flexible and camapart from imposition of the plunger therebetween.
 20. The apparatus ofclaim 12, wherein the expansion device comprises one or more hingedlinkages connected to a distal end of the axially-movable shaft and tothe shape-forming members.